The existing project is a controlled atherosclerosis regression trial using either niacin/colestipol or placebo in men who have had coronary artery bypass surgery. The endpoint is a computer derived comparison of averaged atherosclerosis in 5 cm. segments of femoral artery as seen by angiography at two year intervals. In reviewing the angiograms, it is obvious that the femoral disease is not extensive, but that lesions cluster at inner curvatures or branches. This supplemental application proposes an animal experiment to study the problem of lesion localization. Fourteen minipigs will be maintained on hypercholesterolemic diets and angiogrammed at five month intervals. The location and rate of progression of lesions will be studied. Following this, the animals will be sacrificed and flow replica castings made for hydrodynamic testing. The results of minipig and flow replica studies will be used to augment interpretation of the clinical trial by adding a lesion or lesion site specific measure of atherosclerosis to the segmental measure we now employ. The long-term goal is to develop an improved atherosclerosis endpoint measure for use in future human therapy trials.